ISIS Claims Deadly Paris Attacks, 'First of the Storm'

— -- The terror group ISIS today released a statement claiming responsibility for the horrific, apparently coordinated attacks in Paris Friday that killed more than 100 people.

Calling the attack “blessed,” an audio statement released online in French and Arabic said that ISIS “soldiers” targeted the “capital of prostitution and obscenity, the carrier of the banner of the Cross in Europe.” The statement claimed the attack was the “first of the storm and a warning to those who wish to learn.” An English audio recording, released hours later, repeated the hate-filled message in what sounded like a North American accent.

Today Paris prosecutor Francois Molins said they suspect the gunmen operated in three teams to coordinate the attacks at six locations in Paris. At one of the sites, the Bataclan concert hall, the killers mentioned Iraq and Syria during the massacre. One suspect has been identified as a 30-year-old French citizen, Molins said.

Molins said today seven “terrorists were killed during their criminal actions.” In ISIS's statement, the group had claimed eight “brothers” took part in the operation, the same number of attackers seen in early local media reports. At least 129 people were killed and more than 350 others injured in the attack, Molins said.

Molins said one of the attackers was identified by a Syrian passport found near his body. A Greek official confirms the Syrian passport belonged to someone who had crossed into the European Union as a refugee, through the Greek island of Leros in October.

Officials also revealed that one of the gunmen in the massacre at the concert hall was a 30-year old French citizen who had been flagged as a possible terrorist five years ago but never charged with a serious crime.

Earlier today French President Francois Hollande blamed ISIS, which is based in Syria, for what he called an "act of war."

A senior U.S. intelligence official said that while the U.S. continues "to assess the situation in Paris," American intelligence officers haven't see anything "that contradicts President Hollande's assessment of the situation."

ISIS supporters have repeatedly threatened France, along with other Western nations, as many has a half dozen times this year alone. In July, for instance, a French-speaking purported ISIS fighter said in a video released online that the group would bring “slaughter” to France.

The Department of Homeland Security said Friday it is closely monitoring the events in Paris and said there was no specific or credible threat to the United States. DHS said it's in contact with its counterparts in the area and "will not hesitate to adjust our security posture, as appropriate, to protect the American people."

ABC News' Luis Martinez contributed to this report.